Chinese porcelain decoration: overglaze enamels
The term 'overglaze enamels' is used to describe enamel decoration on the surface of a glaze which has already been fired. Once painted, the piece would be fired a second time, usually at a lower temperature.
The first use of overglaze enamelling is found on the slip-covered wares of northern China. This was an innovation of the Jin dynasty (1115-1234), with documented pieces as early as 1201. These were utilitarian wares, not for imperial use. Under the emperors of the Ming (1368-1644) and the Qing (1644-1911) dynasty, the various techniques of overglaze enamelling reached their heights at the manufacturing centre in Jingdezhen.
The most highly prized technique is known as doucai ('joined' or 'contrasted' colours), first produced under the Ming emperor Xuande (1426-35), but more usually associated with Chenghua (1465-87). Cobalt was used under the glaze to paint the outlines and areas of blue wash needed in the design. The piece was then glazed and fired at a high temperature. Overglaze colours were painted on to fill in the design. The piece was then fired again at a lower temperature.
Wucai wares, meaning 'five colours', were also developed in the Ming dynasty. A full palette of polychrome enamels or mixed colours is used. These pieces tend to be larger than doucai wares, with stronger colours, more intricate designs, and very little white showing. The best-known wucai wares are from the reign of Wanli (1573-1620).
There were also important developments under the Qing dynasty. Famille rose (pink), jaune (yellow), noire (black) and verte (green) were overglaze enamel-decorated porcelains made from the Kangxi period (1662-1722) and later.